Method of pumping and separating liquid and gaseous fluids



June 16, 1964 a. H. MOSBACHER 3,137,234

METHOD OF PUMPING AND SEPARATING LIQUID AND GASEOUS FLUIDS 5 Sheets-Sheet 1 Filed Aug. 10, 1959 June 16, 1964 B. H. MOSBACHER 3,137,234

METHOD OF PUMPING AND SEPARATING LIQUID AND GASEOUS FLUIDS 5 Sheets-Sheet 2 Filed Aug. 10, 1959 June 16, 1964 B. H. MOSBACHER 3,137,234

METHOD OF PUMPING AND SEPARATING LIQUID AND GASEOUS FLUIDS Filed Aug. 10, 1959 5 Sheets-Sheet 3 1171 7%; WW I W United States Patent 6 3,137,234 METHOD OF PUMPING AND SEPARATENG V LIQUID AND GASEGUS FLUHDS Bruce H. Moshacher, Rockford, Iiiassignor to Roper Hydraulics, Inc, a corporation of Georgia Filed-Aug. 10, 1959, er. No. 332,693

3 Claims. (Cl. 103-2) This invention relates toa pumping apparatus, and

particularly to a pumping method and apparatus for separating fluids having diflerent densities.

. An important object of this invention is to provide a method and apparatus for separating fluids having different densities and. which will draw the fluids into the apparatus and deliver the same under pressure to eliminate the necessity of auxiliary pumping apparatus for feeding and withdrawing fluid from the separator.

A more particular object of this invention is to provide a rotary positive displacement pumping apparatus and method of operating, same having a plurality of compartments which rotate to centrifugally separate the fluid therein and which compartments progressively increase in volume in one sector of the pump to draw fluid into the chambers and progressively decrease in volume in another sector to discharge the fluid under pressure,

p and in which the delivery ports are arranged to receive the centrifugally separated fluids todeliver the same in different streams.

Another object of this invention is to provide a pump ing method of apparatus which will separate gas and vapor from a liquid and discharge the same in separated streams to return the vapor to the supply reservoir and deliver the substantially vapor-free liquid to the point of use.

Still another object of this invention is to provide a rotary compressor and method of operating same having an improved system for lubricating the compressor for separating fluids having difierent densities, which the pump broken away and shown in section along the.

line 4-4 of FIG. 5; FIG. 5 is a sectionalview taken on the plane 5-5 of FIG. 4;

FIG. 6 is a sectional view taken "on the plane 6-6 of FIG. 4; 7

FIG. 7 is a diagrammatic view of a rotary compressor having an improved lubricating system, with the pump broken away and shown in'section along the line 7-7 of FIG. 8;

FIG; 8 is a sectional View taken on the plane 8-8.

of FIG. 7; and

FIG. 9 is a sectional view taken on the plane 9-9 of FIG. 7.

This application is a continuation-in-part of my co- 3&37234 pending application SerialNo. 754,096, filed August 8, 1958, now abandoned.

In general, the method of separating fluids having diiierent densities includes a rotary positive displacement pump device, such as a gerotor type pump or a vane type pump. Such rotary pumps define a plurality of rotating compartments which progressively increase in volume to draw fluid into the compartments and then progressively decrease in volume to discharge the fluid under pressure from the compartments. It has been found that the rotation of the fluid in the compartments of such pumps will produce a centrifugal separation of the fluids in the compartments with the heavier fluids lying adjacent the outer periphery of the compartmentsand the lighter fluids disposed adjacent the inner periphery of the compartments. In accordance with the present invention, separate delivery ports are provided and arranged to receive the centrifugally separated fluids and deliver the same in separate streams.

The fluid separating apparatus is generally adapted for use in separating fluids having difierent densities and may be used to separate different liquids such as oil and water which have different densities, and also for separating liquids from gases. While the device is herein illustrated as 'used to separate two different fluids, the apparatus can be modified by the provision of additional ports, suitably arranged, to separate more than two fluids.

Reference is now made more specifically to FIGS. 13 of the drawings wherein there is illustrated an internal gear pump including a housing It and having outer and inner gerotors I1 and I2 therein defining a pumping chamber lh therebetween. The housing 10 is herein illustrated as being formed in a plurality of separate sections including an end wall 13, a port plate 14, an annular side wall 15 and an end wall 16. The aforementioned sections are assembled one on top of the other and retained together by fasteners 17 and, when assembled, define the pump chamber 18 therein between the end wall16 and the port plate 14.

The outer rotor 11 is in the form. of a ring gear and is rotatably received in the chamber 18 for rotation about the axis thereof. The inner rotor 12 is disposed Within the outer rotor and is mounted for rotation about an axis eccentric to the axis of the outer rotor. As here in illustrated, the inner rotor I2 is mounted on a shaft 21 and is non-rotatably connected thereto as by a key .22.

Seals 23 and 24 are provided on the end plates 13 and 16 to prevent leakage of fluid thereby along the shaft 21. As is conventional, the shaft 21 isconnected to a suitable source of power to rotate theinner gear or rotor 12.

The outer rotor 11 has inwardly extending lobes or teeth 27 which mesh with outwardly extending lobes or teeth 23 on the inner rotor-12. In the gerotor type pump shown in FIGURE 1, the lobes 27 and 28 are shaped so that each of the outwardly extending lobes 28 on the inner rotor is disposed, in all operative positions thereof, in close running fit with one of the inwardly extending lobes or teeth 27 on the outer rotor to form a running seal therebetween and separate the pump chamber into a plurality of compartments which rotate with the inner rotor. As the inner rotor 12 is rotated by the shaft 21, the compartments between the inner and outer rotors in one sector of the pump chamber 18 expand and increase in volume andthe compartments between the inner and outer rotors at the other sector of the pump chamber 18 decrease in volume. When the inner rotor is rotated in a counterclockwise direction as indicated by the arrow in FIGURE 1, the compartments at the right hand side of a plane through the axes of the inner and outer rotors are expanding and the compartments at the left hand side of that plane are decreasing in volume. Liquid is sup Patented June I6, 3965 plied from a reservoir 31 and through conduit 32 and passage 33 in the end plate 13 to the generally crescentshaped inlet port 34 formed in the port plate 14. The inlet port is dimensioned to communicate with the compartments at the first sector of the chamber, that is, at the inlet side of the pump, to supply fluid thereto, but terminates short of the plane through the axes of the inner and outer rotors. The fluid entering the pumping chamber through the inlet port 34 is rotated with the inner and outer rotors. When the liquid contains occluded gas or vapor, the relatively light gas will be centrifugally separated from the denser liquid, the denser liquid flowing outwardly into the tooth spaces in the outer rotor 11 and the relatively light vapor and gas being forced inwardly into the intertooth spaces of the inner rotor. Separate outlet ports 33 and 39 are provided for separately discharging the gas and vapor and the substantially vapor-free liquid.

In accordance with the present invention, the first outlet port 38 is disposed at that sector of the chamber at which the compartments diminish in volume, that is, out the side of the plane through the axes of the inner and outer rotors opposite the inlet port 34. The discharge port 38 is angularly spaced in the direction of rotation of the gears from the inlet port to prevent direct communication between the discharge port and the inlet port through the intertooth spaces between the inner and outer rotors. This discharge port is shaped and arranged to communicate with the pockets at the discharge side of the pump in a zone adjacent the roots of the teeth in the inner rotor 12 and spaced radially inward of the roots of the teeth in the outer rotor 11 so that the gas and vapor which has collected adjacent the roots of the teeth in the inner rotor 12 will be forced outwardly through the discharge port 38 as the compartments progressively decrease in volume during rotation of the inner and outer rotors. Preferably, the radially outer edge 38:! of the port 38 is disposed concentric with the axis of the outer rotor 11 and is spaced radially inwardly of the outer rotor. The inner edge 3% of the port 38 is preferably disposed concentric with the axis of the inner rotor 12 so that the area of the port progressively diminishes in the direction of rotation of the gears.

The relatively dense liquid is centrifugally forced outwardly and remainsin the intertooth spaces in the outer rotor 11. This liquid is discharged through the second discharge port 39, which discharge port is angularly spaced in the direction of rotation of the gears from the discharge port 38. The angular spacing between the discharge ports 38 and 39 must be accurately controlled in order to maintain the normally high efficiency of a pump of this type without causing high losses due to trapping of liquid in the space between ports 38 and 39. As shown in FIG. 1, the first and second discharge ports 38 and 39 are spaced substantially one tooth space apart. The leading edge of the second port 39 is arranged so that when the trailing edge of one tooth of the inner rotor 12 begins to uncover the same, the trailing edge of the adjacent tooth on the inner rotor moves out of registry with the first port 38 to provide a seal between the first and second discharge ports without incurring high trapping losses.

The percentage of gas in the liquid supplied at the inlet of the pump will vary in different systems and with different liquids. The relative lengths of the discharge ports are selected so that the portion of the pump displacement discharged through the port 38 exceeds the percentage of gas in the inlet liquid. In the embodiment illustrated, the length of port 38 is arranged so that approximately twenty-five percent of the displacement of the pump is discharged therethrough, the balance being discharged through the other port 39.

The port 38 communicates through a passage 41 in the end plate 13 and through a conduit 42 with the reservoir 31 to return the vapor and gas and whatever liquid is discharged through the port 38 back to the reservoir. As

is conventional, the reservoir 31 is vented, as by means of a vent 44 to permit exhausting of the vapor returned to the reservoir. The other discharge port 39 is connected through a passage 45 in the end plate 13 and through a conduit 46 to the liquid supply line to deliver substantially vapor-free liquid thereto under pressure.

From the foregoing it is thought that the operation of the device will be readily understood. Briefly, the liquid containing gas and occluded air enters the internal gear pump through the inlet port 34 and is centrifugally separated due to rotation of the liquid with the inner and outer rotors 12 and 11 respectively. The relatively light gas is forced inwardly by the denser liquid and is discharged through the first discharge port 38 which is so positioned as to eifect discharging of the vapor while minimizing the discharge of the vapor-free liquid. The substantially vapor-free liquid is then carried in the pockets between the rotors to the second discharge port 39 wherein it is discharged under pressure to the liquid line 46. As is apparent, the single internal gear pump is arranged to operate both as a liquid-vapor separator and also as a boost pump to elevate the pressure on the liquid I delivered to the line 46.

A modified form of fluid separating apparatus employing a rotary vane type pump is illustrated in FIGS. 4-6. In general, the pump housing includes a main body 51 having a concavity 52 in the upper side thereof and a bore 53 for receiving a lower shaft bearing 54. An upper end bell 55 is secured to the body 51 as by fasteners 56 and is sealed to the body by an O-ring 57. The end bell 55 has a bore 53 therein which supports an upper bearing 59. A shaft 61 is rotatably supported in the upper and lower bearings 59 and 54 and is driven by a suitable apparatus diagrammatically indicated at 60 in FIG. 5. A shaft seal (not shown) is provided on the upper end bell to seal the interface between the shaft and the housing. A lower plate 62 overlies the bottom of the body 51 and the bore 53 and is sealed thereto as by O-rings 63. I

An eccentric ring 65 is disposed in the concavity 52 in the pump body 51 and is held against rotation by a pin 66 which extends into the end bell 55. A rotor 68 is non-rotatably connected to the shaft 61 by a key 69. As will be noted from FIG. 4, the outer periphery of the rotor 68 is eccentrically disposed with respect to the inner periphery of the eccentric ring 65. A plurality of vanes 71 are slidably disposed in slots 72 on the rotor and extend into a running seal with the inner wall of the eccentric ring 65, to segregate the chamber into a plurality of compartments which rotate with the rotor and progressively increase in volume in one sector of the chamber and progressively decrease in volume in another sector of the chamber. When the rotor 68 is turned relative to the housing in the direction indicated by the arrow in FIG. 4, the compartments in that sector of the chamber located at the left half of the pump will progressively increase in volume and those compartments located at the right hand side of the pump will progressively decrease in volume. In the embodiment shown, the vanes 71 are centrifugally actuated outwardly into a close running fit with the eccentric ring, it being understood that other conventional means such as springs may be provided for this purpose.

Fluid is supplied to the compartments in that sector of the chamber at which the compartments are progressively increasing in volume through an arcuate inlet port 75. The inlet port 75 terminates short of the plane through the axes of the rotor 68 and the eccentric ring 65 to supply fluid to the compartments as they progressively increase in volume. Fluid is supplied to the port 75 through a passage 76 in the pump body 51 and a conduit 77 from a reservoir 78. The reservoir contains a fluid 79 having components such as liquid and gas which have relatively different densities. The combined fluid is supplied to the compartments and is rotated with the rotor so that the components of the fluid are centrifugally separated. The denser component of the fluid moves to a zone adjacent the outer periphery of the compartments and the lighter component moves to a zone adjacent the inner periphery of the compartments. Separate outlet ports 81 and 82 are provided in that sector of the chamber in which the compartments are progressively decreasing in volume to separately discharge the'heavy and light components of the fluid.

When the fluid being separated contains a gaseous component, it is advantageous to discharge the gaseous component first due to the tendency of the gaseous component to expand. For this purpose, the first discharge or delivery port 81 is angularly spaced in the direction of rotation of the rotor from the inlet port 75 and has the inner edge 81a thereof disposed adjacent the periphery of the rotor 63 and the outer edge 81b thereof SPZilCBd radially inwardly from the eccentric ring 65. The relatively lighter component of the fluid, disposed adjacent the inner. periphery of the compartments, is forced outwardly through the port 8 1 as the compartments progressively decrease in volume. Fluid from the port 81 passes through a passage 82 in the pump body 51 to a conduit 83. In the embodiment shownin FIG. 4, the fluid separating apparatus is arranged to separate air and vapor from liquid to discharge substantially vapor-free liquid,

and for this purpose the conduit 33 is arranged to communicate with the reservoir 78 to return the air and vapor and any liquid that is discharged through the port 81, back to the reservoir. A vent 84 is provided in the reservoir to vent the excess air and vapor therefrom.

The seconddischarge port 82 also communicates with the compartments in that sector of the chamber in which the compartments are decreasing in volume, and is angularly spaced in the direction of rotation of the rotor 68 a distance at least equal to the angular spacing between adjacent vanes 71 on the rotor to prevent communication of theports 81 and 82 through the spaces between vanes.

The relatively denser fluid which remains in the compartments after the lighter fluid is discharged therefrom through port 81, is discharged under pressure through second discharge port 82 to a passage 85 in the pump body 51 which is connected to a delivery conduit 86.

The fluid separating apparatus illustrated in the embodiment of FIGS. 7-9 is arranged for use as a compressor and has provision for delivering lubricant and air in separate streams to the pump and for discharging the air and lubricant in separate streams from the pump, to provide substantially lubricant-free compressed air. The rotary positive displacement pump is of the gerotor type having a pump body 1111 formed with a concavity 102 at its upper side and a bore 103 for receiving a shaft bearing 104. An end bell 105 is secured to the pump body by fasteners 106 and has a bore 107 therein which supports an upper shaft bearing 108. An O-ring 109 is disposed in a groove in the body 1&1 to seal the interface between the end bell and the body and a lower end plate 111 overlies the underside of the pump body and is sealed thereto by O-rings 112 and 113. A shaft 115 is rotatably supported in the upper and lower bearings 108 and 194 and has an enlarged hub 116 having an externally splined portion 117 thereon. An eccentric ring 118 is disposed in the concavity in the body and is held against rotation by a pin 119. An outer gerotor 121 is rotatably supported in the eccentric ring 118 and meshes with an innergerotor 122 which is splined to the hub 116 for rotation therewith. The inner and outer rotors define an eccentric chamber therebetween and the outwardly extending lobes or teeth 122a on the inner rotor are shaped with rotate with the inner rotor. When the inner rotor is rotated in the direction indicated bythe arrow in FIG. 7,

the compartments in that sector of the. chamber located to the left of a plane through the axes of the inner and outer rotors progressively increase in volume, and the compartments located in the sector of the chamber at the right of the aforementioned plane progressively decrease in volume.- a

In accordance/with the present invention, the pump is formed with separate lubricant and air inlet ports designated 125 and 126 respectively, and separate air and lubricant discharge ports designated 127 and 128. The lubricant inlet port 125 communicates with the pump chamber in that sector thereof in which the compartments are increasing in volume so as to draw lubricant into the pump chamber. As shown in FIG. 7, the lubricant port 125 is located closely adjacent the point designated M at which the inner and outer gerotors are in full meshing engagement so as to draw lubricant into the compartments as soon as the volume of the compartments begins to expand. The air inlet port 126 is angularly spaced in the direction of rotation of the rotor. 122 from the first inlet port 25, a distance at least equal to the space between adjacent teeth on the gerotors to maintain a seal beween the inlet ports. Preferably, the outer edge 12 5a of the air inlet port is disposed inwardly of the roots of the teeth of the outer gerotor 121 so as to introduce the relatively lighter air toward the inner periphery of the compartments. Lubricant is supplied to the port 125 through a passage 131 in the pump body 101 and through a conduit 132 leading to a reservoir 133 containing a lubricant 134. Air is supplied to the air inlet port 126 through a passage 137 in the pump body and which is connected to an air intake line 138.

The compressed air delivery port 127 communicates with the compartments in that sector of the chamber in which the compartments are progressively decreasing in volume. As shown in FIG. 7, the port 127 is disposed at the left side of the plane through the axes of the inner and outer gerotors and the arcuate air delivery port is disposed in a zone which communicates with the roots of the teeth of the inner gerotor 122 and is spaced radially from the roots of the teeth in theouter gerotor 121. The relatively heavy lubricant is centrifugally urged outwardly into the roots of the teeth of the outer gerotor, and is not discharged inot the air outlet port 127. The lubricant outlet port 128 also communicates with the compartments in that sector of the chamber in which the compartments are decreasing in volume and is angularly spaced from the air outlet port 127 a distance at least equal to the intertooth spacing of the gerotors to provide a seal therebetween. The lubricant, which remains in the roots of the teeth of the outer gerotor after it has passed the air outlet port 127, is forced out of the intertooth spaces and into the lubricant outlet port 128. The lubricant from the port 128 is conveyed through a passage 141 in the pump body and a conduit 142 back to the lubricant reservoir 133. Any excess air delivered to the reservoir is vented off through a vent 144-. The compressed air from the air outlet port 127 is delivered through a passage 148 in the pump body and conduit 149 to a storage tank 150 or the like. With this arrangement, the lubricant will be drawn into the pump during operation of the same, to lubricate the relatively moving parts, and is then discharged separate from the compressed air back into the reservoir.

From the foregoing it is deemed apparent that the rotary pumping apparatus will draw the fluid into the rotating pump compartments; centrifugally separate the lighter and heavier components of the fluid, and discharge the components in different streams and under pressure. Thus, it is unnecessary to provide additional apparatus for feeding fluid or for withdrawing fluid from the separating apparatus.

The relative sizes of the discharge ports are related so that the change in volume in the compartments as they move past the respective ports is approximately equal to the volume of one of the components of the fluid in the rotating compartments. When it is desired to deliver one component substantially free of the other component, the port for the last-mentioned component is made relatively larger than that required for the volume of that component to assure complete removal thereof. Thus, in the gasliquid separator shown, the gas discharge ports are arranged so that the fluid discharged therethrough exceeds the percentage of gas in the fluid. The liquid which is removed with the air is returned to the reservoir.

While the apparatus is specifically described as used to separate liquid from gases, it is apparent that it is also adapted to separate two immiscible liquids having diflerent densities, such as oil and water. With the arrangements shown in FIGS. 1 and 4, the relatively lighter oil would be discharged through the first delivery port and the heavier water discharged through the second delivery port. Moreover, a third delivery port may be provided adjacent the outer periphery of the chamber, to provide an air-oil-water separator.

I claim:

1. The method of pumping liquid and gaseous fluids of relative different densities and for eflecting substantial centrifugal separation of one of the fluids from the other fluid and for discharging said one fluid under pressure in a stream separate from the other fluid comprising, moving a plurality of expansible and contractible segregated pumping chambers having inner and outer peripheral Walls in an annular path to centrifugally separate the fluids therein to radially inner and outer layers according to the relative densities of the fluids, progressively expanding the volume of the segregated chambers as they move past an inlet zone and progressively contracting the volume of the chambers as they move past a discharge zone, introducing a gaseous fluid and a liquid fluid into the chambers as they move past the inlet zone whereby expansion of the chambers draws the fluids thereinto, and sequentially discharging the gaseous and the liquid fluids from the chambers to first and second separate outlets by venting the chambers to the first outlet only at a point adjacent the inner peripheral wall of the chambers and spaced radially from the outer peripheral wall of the chambers as the chambers move past a first portion of said discharge zone whereby initial contraction of the chambers forces fluid containing the gaseous one of the centrifugally separated fluids to the first outlet, and venting the chambers to the second outlet after the gaseous one of he fluids has been discharged and while the chambers move past a second portion of said discharge zone which is angularly advanced in the direction of rotation of the chambers from the first portion of said discharge zone whereby subsequent contraction of the chambers forces the liquid one of the fluids to the second outlet.

2. The method of claim 1 wherein the fluids are mixed at the time of introduction into the chambers.

3. The method of claim 1 wherein the fluids are introduced separately into the chambers as they move past the first zone.

References Cited in the file of this patent UNITED STATES PATENTS 1,345,895 Seguin July 6, 1920 2,029,742 Sieverts Feb. 4, 1936 2,217,211 Brady Oct. 8, 1940 2,303,589 Sullivan Dec. 1, 1942 2,307,251 Woods et a1 Jan. 5, 1943 2,368,530 Edwards Jan. 30, 1945 2,424,750 Heckert July 29, 1947 2,426,327 Underwood Aug. 26, 1947 2,732,802 Eames Jan. 31, 1956 2,763,336 Erikson Sept. 18, 1956 

1. THE METHOD OF PUMPING LIQUID AND GASEOUS FLUIDS OF RELATIVE DIFFERENT DENSITIES AND FOR EFFECTING SUBSTANTIAL CENTRIFUGAL SEPARATION OF ONE OF THE FLUIDS FROM THE OTHER FLUID AND FOR DISCHARGING SAID ONE FLUID UNDER PRESSURE IN A STREAM SEPARATE FROM THE OTHER FLUID COMPRISING, MOVING A PLURALITY OF EXPANSIBLE AND CONTRACTIBLE SEGREGATED PUMPING CHAMBERS HAVING INNER AND OUTER PERIPHERAL WALLS IN AN ANNULAR PATH TO CENTRIFUGALLY SEPARATE THE FLUIDS THEREIN TO RADIALLY INNER AND OUTER LAYERS ACCORDING TO THE RELATIVE DENSITIES OF THE FLUIDS, PROGRESSIVELY EXPANDING THE VOLUME OF THE SEGREGATED CHAMBERS AS THEY MOVE PAST AN INLET ZONE AND PROGRESSIVELY CONTRACTING THE VOLUME OF THE CHAMBERS AS THEY MOVE PAST A DISCHARGE ZONE, INTRODUCING A GASEOUS FLUID AND A LIQUID FLUID INTO THE CHAMBERS AS THEY MOVE PAST THE INLET ZONE WHEREBY EXPANSION OF THE CHAMBERS DRAWS THE FLUIDS THEREINTO, AND SEQUENTIALLY DISCHARGING THE GASEOUS AND THE LIQUID FLUIDS 